Hydrogen bonding, intermolecular

Keywords Dipole moment Fluorescence Hydrogen bond Intermolecular interactions Solvatochromism... 

KEY TERMS hydrogen bonding intermolecular forces surface tension... 

Commercial PAN is normally produced as an atactic polymer with strong hydrogen-bonded intermolecular forces. Because of repulsion between cyano pendant groups and intermolecular hydrogen bonds, the molecule assumes a crystallizable rodlike conformation. The hydrogen bonds between the rodlike chains create bundles of these chains. PAN may be spun into strong fibers. It has a Tg of 104 C... 

X-ray and time-of-flight (TOF) neutron diffraction and Raman spectroscopic measurements have been carried out at 25°C on concentrated aqueous sulfuric acid solutions, (H2S04),(H20),, x = 0, 0.25, 0.5, 0.75 and 0.86, in order to investigate the hydrogen-bonded intermolecular stmcture in the solutions. The intramolecular parameters for regular tetrahedral SO4 unit were determined from the least squares fit to observed X-ray and neutron interference terms in the range of Q S 8. The nearest neighbor... 

Interaction can be identified as an incompletely resolved peak at r = 2.7 A. This intermolecular distance is 0.2 A shorter than that lor pure water. A well defined first peak at r = 1.7 A observed in the present gN " (r) functions can bo ascribed to the hydrogen-bonded intermolecular O — D interaction. This intermolecular O -O distance is again considerably shorter than that reported for pure liquid water (lb-D = 1-85 These short intermolecular hydrogen-bonded distances indicate the existence of... 

Finally, one interesting way in which electrical effects are interlaced with vibrational effects is in hydrogen bonding. Intermolecular electrical interaction appears to be a dominant factor in understanding red shifts and transition moment enhancements in intramolecular vibrations of hydrogen-bonded molecules [90, 119, 120]. Undoubtedly, there will be other types of molecular problems that are revealed to be dependent on electrical features. The capability for ab initio study of electrical properties paves the way for this to happen. 

Despite their similar behavior at small s (see Fig. 5) the corresponding KSCED results vary significantly. Figs. 6-7 show a very strong dependence of the results on the choice of the enhancement factor F(s) in the GGA approximation for — f°r two hydrogen-bonded intermolecular complexes. Our dedicated... 

Halogen Intramolecular hydrogen bonding Intermolecular hydrogen bonding ... 

Figure 5.12 Hydrogen-bond interactions between 4-OH-tamoxifen and ERa. Hydrogen-bond intermolecular interactions of 4-OH-tamoxifen cocomplexed with human ERa LBD usingtheX-raycrystallographicstructure3ERT at 1.9-A resolution [44] are shown. The conformation was visualized using 3D-Mol...

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